The present invention relates generally to medical devices and methods, and more particularly to a device and method for sealing a puncture site in a blood vessel wall.
In modern medical practice, many clinical procedures require that a catheter or other device be percutaneously inserted into a blood vessel. Such clinical procedures include; diagnostic cardiac catheterization, percutaneous translumenal angioplasties or atherectomies, etc. In many of these procedures, the catheter or other device is typically inserted into the blood vessel by a technique known as the xe2x80x9cSeldinger Techniquexe2x80x9d.
In accordance with the Seldinger Technique, a hollow bore needle is initially inserted into a blood vessel, such as the femoral artery, and a guide wire is subsequently advanced through the lumen of the needle into the blood vessel. The needle is then retracted, leaving the guide wire in place. Thereafter, a tubular introducer having a tapered dilator extending therethrough, is advanced over the guide wire and into the blood vessel. The tapered distal end of the dilator protrudes out of and beyond the distal end of the introducer, to slowly dilate the blood vessel puncture site to a size which is large enough to receive and allow passage of the introducer sheath. The guide wire and dilator are subsequently withdrawn, leaving the introducer sheath in place within the blood vessel. A catheter scope or other device is then passed through the introducer sheath and advanced through the vasculature to its desired location.
After the procedure has been completed, the catheter, scope, or other device and tubular introducer are extracted and removed from the puncture site. Direct pressure is customarily applied to the puncture site to maintain hemostasis, and to minimize hematoma formation. Despite such routine application of direct pressure to the puncture site following the procedure, some localized bleeding, bruising or hematoma formation often occurs. Additionally, other complications, such as pseudoaneurysm formation, may also occur.
The prior art has included a number of methods and devices which are purported to be capable of sealing a vascular puncture site following removal of the percutaneously inserted introducer or the like. For example, one product known by the trade name VASOSEAL(trademark) (Datascope Corporation, Montvale, N.J.) comprises a bolus of collagenous material which is passed through an introducer into the vicinity of the blood vessel puncture site. The deployment of the collagenous material near the blood vessel puncture site is intended to promote coagulum formation, and resultant sealing of the blood vessel puncture site.
Additionally, devices for sealing of blood vessel wall punctures have been described in U.S. Pat. No. 4,829,994 (Kurth), U.S. Pat. No. 4,929,246 (Sinofsky), U.S. Pat. No. 4,744,364 (Kensey) and U.S. Pat. No. 5,108,421 (Fowler).
Also, U.S. patent application Ser. No. 07/959,337 (Taymor-Luria), of which this Application is a continuation-in-part, describes an electrosurgical blood vessel sealing probe which is insertable through a vascular sheath and subsequently retractable to a point where the distal tip of the probe is in contact with blood vessel wall puncture site. Thereafter, electrical energy is applied through the probe to effect electrocauterization or electrocoagulation of the blood vessel wall puncture site. The probe incorporates a guiding means to enhance the operator""s ability to precisely position the distal tip of the probe in its intended position adjacent the blood vessel wall puncture site.
The present invention is directed to bipolar embodiments of the blood vessel sealing probe and method described in parent application Ser. No. 07/959,337 (Taymor-Luria), of which this application is a continuation-in-part.
This continuation-in-part patent application is directed to inventions which comprise bipolar embodiments of a blood vessel sealing probe of the general type disclosed in U.S. patent application Ser. No. 07/959,337. Also, this patent application is directed to methods and apparatus for facilitating operative positioning of a blood vessel sealing device at a location which is immediately adjacent, or at a specific spaced distance from, a blood vessel wall puncture site.
A first embodiment of a bipolar blood vessel sealing probe of the present invention generally comprises an elongate probe or catheter body having a bipolar electrode tip on the distal end thereof, and a bipolar connector on the proximal end thereof. In this embodiment, the bipolar connector is connectable to an electrical power source to provide a flow of electrical current from the connector to the bipolar electrode tip. A guide wire lumen may extend through at least a portion of the probe body, to facilitate advancement of the probe over a pre-inserted guide wire.
A second embodiment of a bipolar blood vessel sealing probe with the present invention generally comprises an elongate probe or catheter body having a single electrode at or near its distal end, and a guide wire which extends longitudinally therethrough so as to protrude out of and beyond the distal end of the probe or catheter body. The region of the guide wire immediately adjacent the distal end of the probe or catheter body forms a second bipolar electrode. Both the guide wire and the elongate probe or catheter body are connectable to an electrical power source to provide a flow of electrical current to the electrode located on the probe or catheter body and the electrode located on the guide wire. In this regard, the electrode located on the probe or catheter body and the electrode located on the guide wire combine to form a bipolar electrode tip whereby electrical energy passes between the probe or catheter body and the guide wire. The guide wire may remain fully or partially inserted into the blood vessel wall puncture so as to facilitate bipolar electrocauterization or electrocoagulation of the blood vessel wall puncture site.
Further in accordance with the invention, the bipolar blood vessel sealing probes of the above-summarized first and second embodiments are useable in combination with an electrical power source. The electrical power source preferably comprises a radio frequency alternating current generator. Because the bipolar probe of the present invention is capable of operating with minimal power, the electrical power source may be preset or limited so as to deliver radio frequency alternating current at power levels below 20 watts, and preferably about 1-10 watts. Additionally, it is preferable that the electrical power be delivered through the probe for discrete periods of time effective to produce electrocauterization or electrocoagulation of the blood vessel wall, while avoiding thermal damage or degradation to the blood vessel wall and/or surrounding tissue. In this regard, a timer may be provided to limit the individual periods of electrical current to approximately 30 seconds-60 seconds each. Additionally, or alternatively, a temperature sensor and feedback control apparatus may be utilized to decrease or terminate the electrical current flowing through the probe when the temperature at the distal end of the probe reaches a predetermined limit.
Further in accordance with the invention, there is provided a non-electrically-conductive guide wire which is usable in connection with the first embodiment of the bipolar blood vessel sealing probe.
Still further in accordance with the invention, there is provided an electrically-conductive electrode-guide wire which is usable with the second embodiment of the bipolar blood vessel sealing probe, said electrically conductive electrode-guide wire forms a second electrode adjacent the distal end of the probe or catheter body, as summarized hereabove with respect to the second embodiment.
Still further in accordance with the invention there are provided methods of sealing puncture sites in blood vessel walls using the bipolar probes and systems of the present invention. In general, the first embodiment of the bipolar blood vessel sealing probe of the present invention may be utilized by positioning the distal end of the probe or catheter body adjacent the blood vessel puncture site and passing electrical current to the bipolar electrode tip so as to effect bipolar electrocauterization or electrocoagulation of the blood vessel puncture site. In contrast, the second embodiment of the bipolar blood vessel sealing probe may be used by a method whereby the distal end of the probe or catheter body is positioned adjacent the outer surface of the blood vessel puncture site and the electrically conductive guide wire is permitted to protrude at least partially through the blood vessel wall puncture site. Thereafter, the electrical current is passed through the probe or catheter body and the electrically conducive guide wire so as to effect bipolar electrocoagulation of the blood vessel puncture site.
Still further in accordance with the invention, a sheath or shield formed of insulating material, such as PTFE (Teflon(trademark)) may be positioned about all or a portion of either the first or second embodiment of the bipolar blood vessel sealing device of the present invention to prevent sticking of the bipolar electrode(s) to the surrounding tissue and/or burning of such surrounding tissue.
Still further in accordance with the invention, there are provided apparatus and methods for positioning or locating the distal end of a vascular sealing probe or device at a position immediately adjacent to, or at a specific spaced distance from, a blood vessel wall puncture site. In general, the preferred apparatus for positioning the distal tip of the probe comprises a notch or depression formed in the outer surface of the probe, at a known distance from the distal tip thereof. As the probe is withdrawn, in the proximal direction, through a blood vessel wall puncture site, the blood vessel wall will elastically engage the notch or depression thereby resulting in increased resistance to further proximal withdrawal. Upon noting such increased resistance, the operator is thereby informed that the probe need only be further withdrawn by a distance equal to the known distance between the notch and the distal end of the probe body. Accordingly, when the increased resistance is noted, the operator may utilize additional pulling force to overcome such increased resistance and, thereafter, to further withdraw the probe in the proximal direction by a distance equal to the known distance between the locator notch and the distal end of the probe body, thereby ensuring that the distal end of the probe body is then positioned immediately adjacent the blood vessel wall puncture site. Alternatively, various other types of apparatus may be utilized to sense the passage of the distal end of the probe out of the blood vessel lumen or to otherwise sense or determine the correct position of the distal end of the probe so as to facilitate positioning of the distal end of the probe at an intended location immediately adjacent to, or a specific spaced distance from, the blood vessel wall puncture site. Examples of such alternative apparatus include, but are not necessarily limited to, a) a bleed back tube or lumen which opens at or near the distal end of the probe to permit visual verification of blood return such that, when the distal end of the probe is extracted from the lumen of the blood vessel, such blood return will cease, b) an electrical impedance measuring apparatus which senses the difference in impedance between the blood vessel wall and the surrounding tissue, c) a flow meter at the distal tip of the probe to determine when the distal tip of the probe is no longer in contact with the flow of blood passing through the blood vessel, d) a thermistor or temperature measuring apparatus operative to sense when dissipation of heat produced by the flowing blood has ceased, thereby indicating when the sensor-site of the thermistor or temperature measuring device has exited lumen of the blood vessel, e) a piezoelectric apparatus operative to determine differences in the electrical potential of the blood, blood vessel wall or tissue surrounding the blood vessel, thereby facilitating determination of when the distal end of the probe has been extracted from the lumen of the blood vessel, and f) an optical apparatus (e.g., a laser) operative to optically discern or determine the type of matter (e.g., blood, vascular wall, connective tissue) which is adjacent an optical sensor located at or near the distal end of the probe.
Further objects and advantages of the invention will become apparent to those skilled in the art upon reading and understanding of the following detailed description, and the accompanying drawing.